Can i just confirm you are opening the CSV file directly into TSM.
If so, it is probably your headers.
Horse can be anything = Horse
Odds needs to be all lowercase = odds
Win/Lose needs to be all lower case and no spaces or backslash = winlose

A quick and easyway or getting a CSV 'template' is to Save as CSV but with no data in it. This will create a CSV file in the correct format with no data.

Remember when opening CSV files that the CSV file cannot be currently open such as open in Excel. You have to close the file to let TSM have access to it.

When copy/pasting the data from Excel or Works, to TSM , you do not include the headers.